ActiveSupport::Notifications and Thread.current

http://api.rubyonrails.org/classes/ActiveSupport/Notifications.html

http://railscasts.com/episodes/249-notifications-in-rails-3

http://web.archive.org/web/20150515174238/http://m.onkey.org/thread-safety-for-your-rails

https://github.com/rails/rails/blob/master/activesupport/lib/active_support/per_thread_registry.rb

https://github.com/rails/rails/blob/master/activesupport/lib/active_support/notifications.rb#L205-L208

https://github.com/rails/rails/blob/master/activesupport/lib/active_support/notifications.rb#L185-L188

https://github.com/rails/rails/blob/master/activesupport/lib/active_support/notifications.rb#L164

https://github.com/steveklabnik/request_store

class RequestRegistry
  extend ActiveSupport::PerThreadRegistry

  attr_accessor :current_user, :current_permissions
end

RequestRegistry.current_user = "user"
puts RequestRegistry.current_user

http://www.justinweiss.com/articles/better-globals-with-a-tiny-activesupport-module/